1. Field of the Invention
The present invention is directed toward beltless conveyors and, more specifically, to a pneumatically actuated beltless conveyor.
2. Description of the Related Art
Conveyors are well known material handling devices which have application in a wide variety of environments for transporting objects from one place to another. For example, one type of conveyor employs a belt formed into an endless loop which is entrained about at least a pair of rollers spaced apart from one another and usually located at the opposed marginal ends of the conveyor. The rollers have sprockets at either end thereof. The spaced rollers are interconnected by a pair of chains entrained about the sprockets at either end of the rollers. An electric or hydraulic motor is usually employed to power the sprockets and continuously moves the belt over a substantial length of the conveyor between the rollers. In this way, objects may be transported by the conveyor over its length.
Conveyors find application in manufacturing environments. For example, in metal stamping operations, conveyors are employed to move parts between successive presses or from a press into a bin. In addition, conveyors are used for inspecting, transporting and assembly situations and can assist in maximizing production by removing parts, slugs or other scrap and materials from under low clearance areas like punch press dies and permitting continuous operation of the press. However, belted conveyors suffer from the disadvantage that the belts are often cut by the sharp edges of the metal parts formed in stamping operations. The useful life of the belts are reduced and the belts must be replaced more frequently. Frequent belt replacement increases the maintenance costs of the stamping operation. Further, stamped parts and other debris may pass through the damaged belts and jam or foul the inner workings of the conveyor drive system.
In part to avoid these problems, beltless conveyors are often employed in certain manufacturing operations. One type of beltless conveyor known in the related art employs magnets to move ferromagnetic parts along the length of the conveyor. Metal parts are supported on a stainless steel or other non-magnetic slide surface. A plurality of strong magnets are movably supported at spaced increments beneath the non-magnetic slide surface along the length of the conveyor. The magnets cause the metal parts to be moved along the slide surface of the conveyor. Beltless magnetic conveyors obviously do not suffer from cuts or worn belts and thus have been adopted in numerous manufacturing environments. Water-tight beltless magnetic conveyors have even been submerged in coolant used in drilling, boring or other metal cutting operations. The magnetic conveyors clean the used coolant of metal or ferromagnetic contaminants so that the coolant may be recycled.
While magnetic conveyors have overcome significant problems associated with the belted conveyors of the related art, disadvantages still exist. Drive systems in both belted and magnetic beltless conveyors employ expensive and complex components. The complexity and expense of such drive systems has become a major factor in limiting the use of conveyors in industry today. Further, as the drive systems have become more complex, the risk that any given component may break, jam or fail has also increased. Conveyors presently employed in the related art are heavy pieces of machinery which are not often portable. In fact, after two to three years, magnetic conveyors are often discarded rather than reused in a different manufacturing line.
Thus, there remains a need in the art for a conveyor that is not susceptible to external damage from including, but not limited to, sharp edges of metal stampings, turnings, chips or parts, which at the same time, does not require a relatively complex drive system which is susceptible to internal damage caused by a failure of complex components. Further, there remains a need in the art for such a conveyor which presents a thin profile, is lightweight and which is also cost-effective.
Partly in response to this need, pneumatically actuated conveyors, commonly referred to as transporters, were developed in the related art. The pneumatic engines are typically mounted to a steel tray designed to convey or transport parts. When compressed air is fed into the transporter, reciprocating forward and reversing motion is created. A critical aspect of this conveying method is the control of the forward and reversing speed and motion cycle. Attaching a tray to this device allows materials to slide along the length of the tray parallel to the forward/reversing direction. This method of conveying materials provides a very cost competitive alternative to belted and magnetic beltless conveyors.
Transporters are very portable, lightweight, small in size and affordable. Trays attached to the transporter can be designed to fit a number of application requirements at a very inexpensive cost. This enables a single transporter to fit a variety of applications, as needs change by simply changing the tray attached to the transporter in applications such as tool changes on a metal stamping press.
Transporters presently employed in the related art utilize compressed air and air seals to operate the pneumatic engine movement. Control of the air in the transporter engine is critical to its effective conveying capability. If the air seal becomes worn or damaged, the transporter will fail to convey materials on the tray. Due to this disadvantage transporters presently employed in the related art are sold with replacement seal kits to maintain the proper control of forward and reversing speed and motion cycle. Replacing seals requires downtime of production process machinery and man-hour labor costs. These costs can often exceed the original cost of the transporter the first time a seal kit is required.
Thus, there continues to be a need in the art for a pneumatically actuated beltless conveyor which presents a thin profile, is lightweight, which does not require the replacement of its engine seals, but which is long lasting as well as cost-effective.